Interest in sports is increasing globally. The continued globalization of sports is enhanced through the mass media and the increased coverage of events. Moreover, participation in sports at all youth and adult recreational levels is burgeoning. Subsequently, increased access is driving demand and as a result, a favorable economic environment has been created that has trickled into the allied supportive industries, such as sports turf management.
Sports turf management involves the establishment and maintenance of athletic fields for the purpose of providing aesthetically pleasing, wear resistant, and safe surfaces for competition. Estimates from surveys indicate that the maintenance of sports turf is a burgeoning industry and is continuing to grow with the interest in a variety of sports and the development of new sports facilities. However, there is continued pressure to maintain superior aesthetic quality under intense use regimes of multiple sports clubs, for the purposes of promoting a high quality television and video product, and maintaining safety at the recreational levels.
Multi-use facilities that host a variety of sporting events must continually confront the problem of residual marking paint used to determine boundaries. Present systems and compositions for removal of paint from turf often are ineffective and hence do not thoroughly remove the previously applied paint. The painting and marking compositions and the compositions for their removal may significantly distort the visual appearance of the turf, discolor the turf, or damage the turf in other ways, or cause the affected areas of turf to be killed. This is of particular concern to sports clubs and associations that share facilities with other sports clubs for logistical and economic reasons. When sporting events are televised, residual marking paint from other sporting events detracts from the quality of the product. In addition, all levels of sports (from town and scholastic to collegiate and professional) are faced with sharing facilities that require a variety of marking patterns.
There are many other situations where a plant or surface needs to be temporarily marked or painted, and then the marking substance or paint later removed without harming the plant or surface. Examples include the surveying industry, such as for road construction or the marking of underground cable, gas, or electrical lines. Other examples include decorative uses, such as Christmas trees or other holiday decorations.
Therefore, there is a need for a non-phytotoxic system of marking and removing plant and other surfaces.
The present invention provides a removable marking system. The system comprises a removable paint formulation comprising zinc oxide, water and an adjuvant, and an aqueous removal formulation having a pH of about 4 to 8, comprising an acid and a buffering agent.
The present invention further provides method of using the system described above by applying the paint formulation and removal formulation to a plant or non-living surface.
The invention is described with reference to various specific embodiments and techniques, however, it should be understood that these specific embodiments and techniques are non-limiting, and that many variations and modifications may be made while remaining within the scope of the invention.
In general, paint compositions used in many industries, including the turf and surveying industries, function by depositing a layer of pigment onto a substrate such as turf or other plants, the ground, rocks, buildings, or other structures. The pigment is typically suspended or solubilized within a carrier fluid that volatilizes or dries after the paint composition is applied, leaving behind a hardened pigment film. Thus, the key performance characteristic of both organic solvent-based and water-based paints is to deposit a permanent film for decoration and/or demarcation. Further, current paints that are designed for application onto plants, such as marking paint for grass on ball fields, contain organic solvents that remove the natural waxy layer on the surface of the grass so that the paint permanently adheres to the plant. Thus, it is not possible to remove these paints from the surface of the blades of grass without harming the grass.
By contrast, the paint formulation of the present invention is non-phytotoxic. In other words, the paint can be applied to the surfaced of a targeted plant and not harm or kill the plant. The paint formulations do not contain organic solvents, as these could potentially harm a target plant.
Further, a key performance characteristic of the paint of the present invention is to deposit a temporary film that easily may be removed without harming or discoloring the surface to which it had been applied. Thus, the aqueous paints of the invention can be used, for example, to mark turf on athletic fields. They may be used by surveyors and landscapers for ground marking, utility line identification or as road markers. Paints of the invention are also very useful for marking tanks and lumber for identification purposes. The paint of the present invention is preferred over presently available formulations in that if it were accidentally sprayed onto surrounding plants, it would not harm the plants, and could be readily removed from the plants without harming the plants.
The system of the present invention also provides a removal formulation that is non-phytotoxic and does not contain organic solvents. When the removal formulation is applied to the paint formulation of the present invention that has been applied to a living or non-living surface, the acid in the removal formulation combines with the zinc oxide to produce harmless zinc acetate. The paint formulations and removal formulations will be described in detail below, as well as a description of the method of using the paint and removal formulation.
I. Paint Formulations
The paint formulations of the present invention are water-based and contain zinc oxide. Zinc oxide is useful because it is relatively inexpensive and is commercially available from several suppliers (e.g., Aldrich Chemical Company, Milwaukee, Wis., U.S.A. and the Sigma Chemical Company, St. Louis, Mo., U.S.A.). Zinc oxide is also useful because it is white, the preferred color for most athletic fields. Also, colored pigments can be easily added to the paint formulation if other colors are desired. Colored pigments useful in the formulations of the invention are readily available from commercial suppliers. The zinc oxide of the present invention is present in the paint formulation at a concentration in the range of about 10% to 30%. In particular, the concentration of the zinc oxide is about 20%.
A propellant can be combined with aqueous paint suspensions of the invention to provide an aqueous aerosol paint. Suitable propellants do not react with any of the other components of the paint and do not adversely affect the film-forming properties of the paint when sprayed onto a substrate surface. For example, the propellant can be condensed air, or CO2. The paints of the invention may be formed by adding an amount of aqueous paint suspensions into an aerosol can or tube, crimping a valve onto the shoulder of the can or tube, drawing a vacuum on the sealed and filled can or tube, and then charging the filled can or tube through the valve stem with an appropriate amount of propellant.
An adjuvant, also called a surfactant in the industry, is added to the paint formulation and/or removal formulation. Such adjuvants assist in allowing the paint or removal formulation to be evenly spread onto the target surface and to prevent it from beading up on the target surface. The adjuvant also assists in having the paint remain adhered to the target surface, such as grass, even if it comes into contact with another surface, such as the feet of a soccer player. The adjuvant also assists in having the paint in being xe2x80x9crainfast,xe2x80x9d i.e., the paint remains oh the target surface through a rain or irrigation event. The adjuvant used in the present invention includes spray adjuvants. In particular, the adjuvant is a non-ionic spreader/sticker, including, but not limited to, synthetic latex and organosilicone surfactants: polymers of xcex1-pinene: alkanolamine surfactants, alkylaryl polyethoxyethanol sulfates, and 1,2-propanediol; and di-1-p-menthene. Examples of adjuvants useful in the present invention include COHERE(copyright) brand adjuvant alkanolamine surfactants, alkylaryl polyethoxyethanol sulfates, and 1,2-propanediol), TACTIC(copyright) brand adjuvant (synthetic latex and organosilicone surfactant fluid) LASTICK(copyright) brand adjuvant (di-1-p-menthene) and TRANSFIX(copyright) brand adjuvant (polymer of xcex1-pinene). COHERE(copyright) brand adjuvant is commercially available from Helena Chemical Company, Memphis, Tenn., USA; TACTIC(copyright) brand adjuvant is available adjuvant from Loveland Industries, CO, USA; LASTICK(copyright) brand adjuvant is available adjuvant from Helena; and TRANSFIX(copyright) brand adjuvant is available adjuvant from Cenex, MN, USA. In a preferred embodiment, COHERE(copyright) brand adjuvant is selected.
Thus, the removable paint formulation of the present invention is an aqueous paint that contains zinc oxide, an adjuvant, and optionally colored pigments and/or a propellant. It should be noted that the paint formulation of the present invention can adhere to the outer natural surface of a plant, such as the natural waxy substance on the surface of a blade of grass. It does not require the removal of this waxy substance in order to sufficiently adhere like other field paints that use organic solvents to permanently adhere the paint to the plant surface.
II. Removal Formulations
The removal formulations of the present invention are aqueous formulations with a pH of about 4 to 8 containing an acid and a buffering agent. The formulations may optionally contain a propellant. Like the paint formulation of the present invention, the removal formulation of the present invention is non-phytotoxic.
Acids useful in the present invention are weak acids. The preferred acid is acetic acid (e.g., Aldrich Chemical Company, Milwaukee, Wis., U.S.A. and the Sigma Chemical Company, St. Louis, Mo., U.S.A.). The acid in the removal formulation is present in a concentration range of about 3.5% to 6%. Preferably, the acid is present at a concentration of about 4.5%.
The pH of the removal formulation is important so that it does not harm the target plant. The range of the removal formulation should be about 4 to 8, even about 4.5 to 7.5. The preferred pH is about 6 to 6.5.
The buffering agent in the removal formulation can be a weak base. Preferably, the buffering agent is NH4OH. The buffering agent in the removal formulation is present in a concentration range of about 1.5% to 3%. Preferably, the buffering agent is present at a concentration of about 1.875%.
The removal formulation does not contain organic solvents, as these could harm a target plant.
III. Method of Use/Administration of Removable Marking System
The method of the present invention involves the application of a paint formulation of the present invention onto a plant or non-living surface, followed by the application of a removal formulation of the present invention. The removal formulation may be followed with a water drench. For example a wash step may be applied within about five minutes of the application of the removal formulation.
The paint and removal formulations may be administered repeatedly to the same target, such as a ball field. The paint and removal formulations will not harm a living surface, such as turf grass, even with repeated administrations.
When used herein, the term xe2x80x9cadministerxe2x80x9d includes, but is not limited to, the direct application of a paint formulation to a plant or non-living surface via spray, dusting, or direct application by hand. For purposes of this invention, the paint and/or removal formulations can be applied singly or repeatedly. The formulations can be applied as a liquid, as a crude mixture, or as an agronomic formation. Agronomic formulations include, for example, solutions, liquid suspensions, emulsions, wettable powders, dusts, emulsifiable concentrates, aerosols, and granular formulations. In general, the paint formulations are present in a dispersed or readily dispersible form. Dispersibility promotes thorough and uniform coverage of, or contact with, any plant or turf, or any target plot of soil. In some situations a wetting or dispersing agent, or other active ingredients may be added. The paint and/or removal formulations can be applied to the target surface through available turf marking paint equipment, or other commercially available applicators.
It will be understood, of course, that a choice of concentration of paint formulation depends upon the method of application as well as the type of formulation and the degree of decoration or demarcation desired.
The following examples are intended to illustrate but not limit the invention.